Adhesively bonded assemblies with identical nondeformable adherends and nonhomogeneous adhesive layer: Predicted thermal stresses in the adhesive

We consider a thermoelastic problem for an adhesively bonded assembly with identical nondeformable adherends and nonhomogeneous adhesive layer: its mi dportion has a larger coefficient of thermal expansion (contraction), large r Young's modulus and smaller Poisson's ratio than the peripheral portions. An elongated assembly is examined, and the case when the assembly is manuf actured at an elevated temperature and is subsequently cooled down to a low temperature is addressed. The objective of the analysis was to develop a simple stress model for the evaluation of the thermally induced stresses and displacements in the adhes ive layer. These arise because of the thermal contraction mismatch of the a dhesive material with the material of the adherends, as well as because of the mismatch of the material in the midportion of the adhesive layer with t he material in the peripheral portions. We conclude that sufficiently long peripheral portions can reduce substantially the stresses and the distortio ns of the cross-sections in the mid-portion of the adhesive layer, thereby resulting in a situation when an appreciable inner region of the midportion has a uniform state of stress and strain, and next-to-zero longitudinal di splacements. The obtained results can be helpful in the analysis and design of adhesively bonded assemblies of the type in question.